This invention relates to an improvement of a roller type linear movement guiding device adapted to guide a moving object such as a table which moves straightly on the frame of a machine, in which a plurality of roller circulation type linear movement guiding bearings are arranged side by side to share the load equally.
A conventional roller type linear movement guiding device of this type is as shown in FIGS. 10 and 11. In the device, a plurality of roller type linear movement guiding bearings 3 (four bearings 3 in FIGS. 10 and 11) are arranged on the flat track surface 2 of a guide rail 1, and are surrounded by the right, left, front and rear side boards 4 of a holding board 5 so that they may not be moved away from one another. Each of the roller type linear movement guiding bearings 3 comprises a number of rollers 22 which circulate (revolve) infinitely while rolling. Therefore, the bearing 3 can be smoothly moved on the track surface of the guide rail 1 in the axial direction as the rollers 22 roll. On each of the bearings 3, there is provided a fitting plate 7. The latter 7 is T-shaped in section so as to reduce the load area and to concentrate the load at the center of the bearing. The holding board 5 is supported by the fitting plates 7, so that a load W applied to the holding board is shared equally by the fitting plates 7 and accordingly by the load rollers of the bearings 3.
As is apparent from the above description, in the conventional roller type linear movement guiding device, the weight of an object to be conveyed is supported by the whole upper surface 5a of the holding board 5 which is supported by the plurality of roller type linear movement guiding bearings 3. Hence, the inclination (indicated at .theta.) in right-and-left direction of the object ("rolling") or the inclination (indicated at .alpha.) in front-and-rear direction of the same ("pitching") which occurs for instance because of the assembling error of the device, is not automatically corrected. Hence, in this case, unbalanced loads are applied to the particular ones of the roller type linear movement guiding bearings 3 as indicated at W.sub.1 and W.sub.2. As a result, a trouble occurs with the device; for instance the bearings 3 may be twisted.